Back in Australia, the senator, an independent in parliament, told Radio Australia's Pacific Mornings his deportation is curious, "given that I was to meet a senior government minister and the election commission with some of my colleagues."

"Clearly there are some in the Malaysian Government who are very worried about the forthcoming elections," he added.

Senator Xenophon had travelled to Malaysia with other Australian parliamentarians at the invitation of the Malaysian transparency and electoral reform group Bersih, or "Clean".

"So we weren't being interfering Australians."

But Malaysia's Gerakan Party, part of the ruling coalition, has defended the decision to deport Senator Xenophon.

I fully agree with his deportation, we do not welcome him in Malaysia.

He should not have interfered with the political scenario in Malaysia.

I think he has to mind his own business.

Tan Keng Liang, the Gerakan Party's youth chief in Kedah state

The party's youth chief in Kedah state, Tan Keng Liang, has told Radio Australia's Asia Pacific that Malaysia is not a dictatorship and does not need lessons on democracy from an Australian politician.

"In the past, we noted that Mr Xenophon had supported the movement of Bersih," he said.

"Bersih has held a street demonstration last year, which ended up as a violent street demonstration, and has caused severe injuries to Malaysians and destruction of public property.

"Therefore, I have no objection in our government in deporting Mr Xenophon."

Mr Tan, who is also a practicing lawyer, says Senator Xenophon should have been told in advance he was not welcome.

"I think that the Malaysian Government may have made a mistake - they should have informed Mr Nick Xenophon that he was not welcome in Malaysia in advance," he said.

"That I believe is a mistake. But I have no issue - and I fully agree - with his deportation, we do not welcome him in Malaysia.

"He should not have interfered with the political scenario in Malaysia. I think he has to mind his own business."

'Unusual circumstance'

The South Australian senator had been about to join a delegation which had meetings planned with Malaysian opposition members and officials from the electoral commission ahead of this year's national election.

Instead he was detained, in a move Australia's Foreign Minister Bob Carr has described as sad and disappointing.

The Australian Opposition's foreign affairs spokeswoman, Julie Bishop, says it was "unusual" for Malaysia to detain an Australian senator.

Ms Bishop says Australia must ensure it maintains a strong relationship with its close neighbour.

"It's clearly a very unusual circumstance for an Australian member of parliament to be denied entry to Malaysia and we do await a full explanation from the Malaysian Government," she said.

Malaysian MP Nurrul Izzah Anwar, who is the daughter of Opposition leader Anwar Ibrahim, has criticised the decision to deport Senator Xenophon and his delegation from Malaysia.

Ms Nurrul Izzah told Australia Network's Newsline that his visit was aimed at strengthening democracy in Malaysia, and he had "not broken any Malaysian laws."

"What's wrong with having an Australian senator, legislator, coming to Malaysia to observe the electoral system," the vice president of the Opposition PKR said.

"If [President Najib Razak] has nothing to hide, then he should not stop Senator Xenophon or anyone else from coming into Malaysia."

Senator Xenophon, who is outspoken on human rights issues in Malaysia, told a media conference back in Australia he was relieved to be home.